There is a known issue where Wikidot's base CSS doesn't seem to include the button GIFs in the editor, however I'm not prepared to look into resolving that issue. If others are willing, I recommend appending the CSS fix to the Emulated Base CSS.

Feel free to test this with your own sites. I know that I'd probably enjoy using my existing layouts but moving the editor to above the page content instead of below it :-)

Good stuff, James. You were a busy boy!
I'm looking forward to applying your handiwork to one of my sites. One of my longtime annoyances was having the search box and login status trapped inside the header.